JP2015059857A - Search device for ground fault position - Google Patents

Search device for ground fault position Download PDF

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JP2015059857A
JP2015059857A JP2013194278A JP2013194278A JP2015059857A JP 2015059857 A JP2015059857 A JP 2015059857A JP 2013194278 A JP2013194278 A JP 2013194278A JP 2013194278 A JP2013194278 A JP 2013194278A JP 2015059857 A JP2015059857 A JP 2015059857A
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measurement signal
cable
ground fault
power supply
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JP5844327B2 (en
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明宏 小川
Akihiro Ogawa
明宏 小川
潔 畑
Kiyoshi Hata
潔 畑
光男 高田
Mitsuo Takada
光男 高田
臨 木束地
Rin Kizukaji
臨 木束地
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Chugoku Electric Power Co Inc
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Abstract

PROBLEM TO BE SOLVED: To quickly and easily specify a ground-faulted cable.SOLUTION: A search device of a ground fault position includes: an AC power supply; a switch for selectively connecting the AC power supply to a positive electrode side cable and negative electrode side cable connected between a DC power supply and a load; a measurement device for, when the AC power supply is connected to the positive electrode side cable, measuring a variable magnetic field due to currents flowing through the positive electrode side cable to output a first measurement signal, and for, when the AC power supply is connected to the negative electrode side cable, measuring the variable magnetic field due to currents flowing through the negative electrode side cable to output a second measurement signal; and a determination device for comparing the first measurement signal with the second measurement signal, and for, when the first measurement signal is different from the second measurement signal, determining that either the positive electrode side cable or the negative electrode side cable is ground-faulted.

Description

本発明は、地絡箇所の探索装置に関する。   The present invention relates to a ground fault location searching apparatus.

変電所で使用される遮断器や変速器などの機器の制御用電源として直流電源が用いられている。上記機器と直流電源との間を接続するために、多数のケーブルが変電所構内にわたって埋設されたり敷設されたりされて、直流回路網が形成されている。なお、上記直流回路網に含まれる個別の回路は、制御室から制御される。   A DC power source is used as a power source for controlling devices such as circuit breakers and transmissions used in substations. In order to connect between the equipment and the DC power source, a large number of cables are buried or laid across the substation premises to form a DC network. The individual circuits included in the DC circuit network are controlled from the control room.

このような直流回路網において、ケーブルの損傷により地絡故障が発生することがあり、その場合、制御室においてエラーが表示される。   In such a DC network, a ground fault may occur due to cable damage, in which case an error is displayed in the control room.

従来、地絡箇所の探索は、例えば次の手順１〜手順３のように行われている。   Conventionally, a search for a ground fault location is performed as in the following procedure 1 to procedure 3, for example.

手順１： 制御室に設けられた個別の回路のスイッチを１つずつ切っていき、エラーが解消されるかどうかを確認することで、地絡している線路を特定する。 Procedure 1: Switch off individual circuits provided in the control room one by one, and identify whether the ground fault is present by checking whether the error is resolved.

手順２： 地絡している線路に含まれるケーブルを部分的に切り離し、地絡しているケーブルを特定する。 Procedure 2: Partially disconnect the cable included in the grounded track and identify the grounded cable.

手順３： 地絡しているケーブルを目視により点検し、損傷箇所を探しだす。 Procedure 3: Visually inspect the grounding cable to find the damaged part.

特にケーブルが複数本まとめて埋設されたり敷設されたりしている場合には、手順２と手順３は時間と労力を要する。 In particular, when a plurality of cables are buried or laid together, procedure 2 and procedure 3 require time and labor.

また、例えば特許文献１および２に開示されているような地絡箇所の探索装置および検出方法が提案されている。   Further, for example, a ground fault location searching apparatus and a detection method as disclosed in Patent Documents 1 and 2 have been proposed.

特開平８−９４６９９号公報JP-A-8-94699 特開２０００−２８４０１５号公報JP 2000-284015 A

しかし、特許文献１および２の探索装置および検出方法を用いた場合でも、まとめて埋設されたり敷設されたりしている状態における複数本のケーブルから、地絡しているケーブルを特定することが、時間を要する作業であることに変わりはない。   However, even when the search device and the detection method of Patent Documents 1 and 2 are used, it is possible to identify a grounded cable from a plurality of cables in a state where they are buried or laid together, This is a time-consuming task.

前述した課題を解決する主たる本発明は、交流電源と、直流電源と負荷との間に接続されている正極側ケーブルおよび負極側ケーブルに対して前記交流電源を選択的に接続するスイッチと、前記交流電源が正極側ケーブルに接続されているとき、前記正極側ケーブルを流れる電流による変動磁場を測定して第１測定信号を出力し、前記交流電源が負極側ケーブルに接続されているとき、前記負極側ケーブルを流れる電流による変動磁場を測定して第２測定信号を出力する測定装置と、前記第１測定信号と前記第２測定信号とを比較して、前記第１測定信号と前記第２測定信号が異なる場合、前記正極側ケーブルおよび前記負極側ケーブルのいずれか一方に地絡が発生していると判定する判定装置と、を備える。   The main present invention for solving the above-mentioned problems is an AC power source, a switch that selectively connects the AC power source to a positive side cable and a negative side cable connected between the DC power source and a load, When the AC power source is connected to the positive side cable, the variable magnetic field due to the current flowing through the positive side cable is measured to output a first measurement signal, and when the AC power source is connected to the negative side cable, A measurement device that measures a varying magnetic field due to a current flowing through the negative cable and outputs a second measurement signal, and compares the first measurement signal with the second measurement signal, and compares the first measurement signal with the second measurement signal. And a determination device that determines that a ground fault has occurred in either one of the positive cable and the negative cable when the measurement signals are different.

本発明の他の特徴については、添付図面及び本明細書の記載により明らかとなる。   Other features of the present invention will become apparent from the accompanying drawings and the description of this specification.

本発明によれば、速やかにかつ簡便に、地絡しているケーブルを特定することができる。   According to the present invention, it is possible to quickly and easily identify a grounded cable.

本発明の第１実施形態における地絡箇所の探索装置の概略を示す図である。It is a figure which shows the outline of the search apparatus of the ground fault location in 1st Embodiment of this invention. 本発明の第１実施形態における判定装置を示す図である。It is a figure which shows the determination apparatus in 1st Embodiment of this invention. 本発明の第２実施形態における判定装置を示す図である。It is a figure which shows the determination apparatus in 2nd Embodiment of this invention.

本明細書および添付図面の記載により、少なくとも以下の事項が明らかとなる。   At least the following matters will become apparent from the description of this specification and the accompanying drawings.

[第１実施形態]
以下、図１および図２を参照して、本発明の第１実施形態における地絡箇所の探索装置および探索方法について説明する。
なお、本実施形態において、直流電源ＥＤ、２つの負荷５（５１，５２）、および、直流電源ＥＤと負荷５（５１，５２）との間をそれぞれ接続する正極側および負極側ケーブル６（６１ｐ，６１ｎ、６２ｐ，６２ｎ）は、直流回路網を形成している。また、Ｃｇはケーブル６（６１ｐ，６１ｎ、６２ｐ，６２ｎ）と大地との間の対地静電容量を表す。本実施形態では、特に明示のない限り、負荷５２に接続されている負極側ケーブル６２ｎにおける位置Ｆで地絡事故が発生したものとする。 [First embodiment]
Hereinafter, with reference to FIG. 1 and FIG. 2, a ground fault location searching apparatus and searching method according to the first embodiment of the present invention will be described.
In the present embodiment, the DC power supply ED, the two loads 5 (51, 52), and the positive and negative cables 6 (61p) connecting the DC power supply ED and the load 5 (51, 52), respectively. , 61n, 62p, 62n) form a DC network. Cg represents the electrostatic capacitance between the cable 6 (61p, 61n, 62p, 62n) and the ground. In the present embodiment, it is assumed that a ground fault has occurred at position F in the negative electrode side cable 62n connected to the load 52 unless otherwise specified.

＝＝＝構成および動作＝＝＝
図１は、本実施形態における地絡箇所の探索装置の概略を示す。図１に示されるように、地絡箇所の探索装置１は、交流電源Ｅａ、スイッチＳＷ、磁気センサ２および判定装置３を備える。交流電源Ｅａは、例えば数百Ｈｚの周波数の電圧を発生させ、好ましくは６００Ｈｚの周波数の電圧を発生させる。数百Ｈｚの周波数を採用するのは、後述するように、判定装置３において、対地充電電流ＩＣｇおよび地絡電流Ｉｒに伴う微弱な変動磁場と環境磁場とに由来する成分を含む測定信号Ｓから、変動磁場の成分が検出されるようにするためである。６００Ｈｚほどの比較的高い周波数の場合には、測定信号Ｓから変動磁場に由来する成分の検出はより容易になる。 === Configuration and Operation ===
FIG. 1 shows an outline of a ground fault location searching apparatus in the present embodiment. As shown in FIG. 1, the ground fault location searching device 1 includes an AC power source Ea, a switch SW, a magnetic sensor 2, and a determination device 3. The AC power supply Ea generates a voltage having a frequency of, for example, several hundred Hz, and preferably generates a voltage having a frequency of 600 Hz. The frequency of several hundred Hz is adopted from the measurement signal S including a component derived from the weakly varying magnetic field and the environmental magnetic field associated with the ground charging current ICg and the ground fault current Ir in the determination device 3 as described later. This is because the component of the varying magnetic field is detected. In the case of a relatively high frequency of about 600 Hz, it becomes easier to detect a component derived from the varying magnetic field from the measurement signal S.

また、スイッチＳＷは、交流電源Ｅａを正極側ケーブル６１ｐ，６２ｐおよび負極側ケーブル６１ｎ，６２ｎに選択的に接続する。スイッチＳＷが一方の極性のケーブルに接続された場合、磁気センサ２が、判定装置３で比較される程度の大きさの測定信号Ｓ（Ｓ１ｐ，Ｓ１ｎ，Ｓ２ｐ，Ｓ２ｎ）を出力するまで、その極性のケーブルへの接続は維持される。なお、スイッチＳＷの切替は例えば手動により行われる。なお、後述するように、地絡ケーブルの判定後に、磁気センサ２を地絡ケーブルに沿って走査することで地絡箇所の探索が行われる。その場合には、磁気センサ２による走査の間、スイッチＳＷは地絡ケーブルの側に接続される。   The switch SW selectively connects the AC power source Ea to the positive side cables 61p and 62p and the negative side cables 61n and 62n. When the switch SW is connected to a cable of one polarity, the polarity of the magnetic sensor 2 is output until the magnetic sensor 2 outputs a measurement signal S (S1p, S1n, S2p, S2n) having a magnitude comparable to that of the determination device 3. The connection to the cable is maintained. Note that the switch SW is manually switched, for example. As will be described later, after the ground fault cable is determined, the ground fault location is searched by scanning the magnetic sensor 2 along the ground fault cable. In that case, the switch SW is connected to the ground fault cable side during scanning by the magnetic sensor 2.

磁気センサ２は、ケーブル６（６１ｐ，６１ｎ、６２ｐ，６２ｎ）に流れる電流によって生ずる変動磁場を測定し、測定信号を出力する測定装置である。磁気センサ２は、地磁気や変圧器からの磁気などによる環境磁場の中から微弱な上記変動磁場を検出するように、例えば超伝導量子干渉計（superconducting quantum interferometer device；以下、ＳＱＵＩＤと言う）グラジオメータである。   The magnetic sensor 2 is a measuring device that measures a varying magnetic field generated by a current flowing through the cable 6 (61p, 61n, 62p, 62n) and outputs a measurement signal. The magnetic sensor 2 is, for example, a superconducting quantum interferometer device (hereinafter referred to as SQUID) gradiometer so as to detect the above-mentioned weak magnetic field from the environmental magnetic field due to geomagnetism or magnetism from a transformer. It is.

本実施形態におけるＳＱＵＩＤグラジオメータは、磁場を捕捉する検出コイルとＳＱＵＩＤ本体とを含む。ＳＱＵＩＤ本体が環境磁場などの影響を受けないように、検出コイルはＳＱＵＩＤ本体から分離している。検出コイルは、互いの入力を打ち消し合うように同一平面上に配置された一対のピックアップコイルを含み、一対のピックアップコイルのそれぞれに入力された信号の差分がＳＱＵＩＤ本体に出力される。個々のピックアップコイルの寸法はケーブル６の直径とほぼ同じの大きさである。例えば、一方のピックアップコイルがケーブル６の近傍に配置され、他方のピックアップコイルが上記一方のピックアップコイルよりもケーブル６から離れて配置されているときのように、両ピックアップコイルに鎖交する磁束に差がある場合に、検出コイルは、両ピックアップコイルの入力の差分をＳＱＵＩＤ本体に伝達する。なお、検出コイルは例えば手動により操作される。   The SQUID gradiometer in the present embodiment includes a detection coil that captures a magnetic field and a SQUID body. The detection coil is separated from the SQUID body so that the SQUID body is not affected by an environmental magnetic field or the like. The detection coil includes a pair of pickup coils arranged on the same plane so as to cancel each other's input, and a difference between signals input to each of the pair of pickup coils is output to the SQUID body. The size of each pickup coil is almost the same as the diameter of the cable 6. For example, when one pickup coil is arranged in the vicinity of the cable 6 and the other pickup coil is arranged farther from the cable 6 than the one pickup coil, the magnetic flux interlinked with both pickup coils is generated. When there is a difference, the detection coil transmits the difference between the inputs of both pickup coils to the SQUID body. The detection coil is manually operated, for example.

本実施形態において、健全なケーブル６１ｐ，６１ｎ、６２ｐには、ほぼ同じ大きさの対地充電電流ＩＣｇがそれぞれ流れるのに対して、地絡の生じているケーブル６２ｎの位置Ｆより交流電源Ｅａ側の部分には、対地充電電流ＩＣｇに加えて地絡電流Ｉｒが流れる。従って、ケーブル６１ｐ，６１ｎ、６２ｐに対する磁気センサ２の測定信号Ｓ１ｐ，Ｓ１ｎ，Ｓ２ｐはほぼ同じ大きさであるのに対して、ケーブル６２ｎにおける位置Ｆより交流電源Ｅａ側の部分に対する磁気センサ２の測定信号Ｓ２ｎは測定信号Ｓ１ｐ，Ｓ１ｎ，Ｓ２ｐより大きい。また、ケーブル６２ｎにおける位置Ｆより負荷側の部分には対地充電電流も地絡電流も流れないため、磁気センサ２から出力される測定信号は０である。よって、磁気センサ２の検出コイルをケーブル６２ｎに沿って、交流電源Ｅａ側から位置Ｆを経て負荷５２側へ走査するとき、測定信号Ｓ２ｎは、位置Ｆを境にして、上述した相対的に大きな値から０に変化する。なお、対地充電電流ＩＣｇおよび地絡電流Ｉｒは、交流電源Ｅａの周波数とほぼ同じ周波数を持ち、磁気センサ２の出力する測定信号Ｓ１ｐ，Ｓ１ｎ，Ｓ２ｐ，Ｓ２ｎもまた、ケーブル６２ｎにおける位置Ｆより負荷側の測定信号を除き、交流電源Ｅａの周波数とほぼ同じ周波数を持つ。   In the present embodiment, ground charging currents ICg having almost the same magnitude flow through the healthy cables 61p, 61n, and 62p, respectively, whereas the position F of the cable 62n where the ground fault occurs is closer to the AC power supply Ea side. In the portion, the ground fault current Ir flows in addition to the ground charging current ICg. Accordingly, the measurement signals S1p, S1n, and S2p of the magnetic sensor 2 for the cables 61p, 61n, and 62p are substantially the same magnitude, whereas the measurement of the magnetic sensor 2 for the portion on the AC power supply Ea side from the position F in the cable 62n. The signal S2n is larger than the measurement signals S1p, S1n, S2p. In addition, since the ground charging current and the ground fault current do not flow in the portion on the load side from the position F in the cable 62n, the measurement signal output from the magnetic sensor 2 is zero. Therefore, when the detection coil of the magnetic sensor 2 is scanned along the cable 62n from the AC power supply Ea side to the load 52 side through the position F, the measurement signal S2n is relatively large with the position F as a boundary. Change from value to zero. The ground charging current ICg and the ground fault current Ir have substantially the same frequency as that of the AC power supply Ea, and the measurement signals S1p, S1n, S2p, S2n output from the magnetic sensor 2 are also loaded from the position F in the cable 62n. Except for the measurement signal on the side, it has substantially the same frequency as that of the AC power supply Ea.

判定装置３は、交流電源Ｅａが正極側ケーブル６１ｐ，６２ｐに接続されている場合に磁気センサ２からそれぞれ出力される測定信号Ｓ１ｐ，Ｓ２ｐと、交流電源Ｅａが負極側ケーブル６１ｎ，６２ｎに接続されている場合に磁気センサ２からそれぞれ出力される測定信号Ｓ１ｎ，Ｓ２ｎとを比較して、これら測定信号が異なるとき、ケーブル６のいずれかに地絡が生じていると判定する。本実施形態では、測定信号Ｓ１ｐ，Ｓ１ｎ，Ｓ２ｐと測定信号Ｓ２ｎとは異なっているから、例えば、測定信号Ｓ１ｐとＳ１ｎ、Ｓ２ｐとＳ２ｎがそれぞれ判定装置３において比較される場合には、ほぼ同じ信号であるＳ１ｐとＳ１ｎに対応するケーブル６１ｐと６１ｎに地絡は生じておらず、異なる信号であるＳ２ｐとＳ２ｎに対応するケーブル６２ｐと６２ｎのいずれかに地絡が生じていると判定する。更に、測定信号Ｓ２ｎは、ケーブル６２ｎにおける位置Ｆより交流電源Ｅａ側の部分では、測定信号Ｓ１ｐ，Ｓ１ｎ，Ｓ２ｐより大きいから、判定装置３は、ケーブル６２ｎに地絡が生じていると判定する。   In the determination device 3, when the AC power source Ea is connected to the positive cables 61p and 62p, the measurement signals S1p and S2p output from the magnetic sensor 2 and the AC power source Ea are connected to the negative cables 61n and 62n, respectively. The measurement signals S1n and S2n respectively output from the magnetic sensor 2 are compared, and when these measurement signals are different, it is determined that a ground fault has occurred in any of the cables 6. In the present embodiment, the measurement signals S1p, S1n, S2p are different from the measurement signal S2n. For example, when the measurement signals S1p and S1n and S2p and S2n are compared in the determination device 3, respectively, substantially the same signal It is determined that a ground fault has not occurred in the cables 61p and 61n corresponding to S1p and S1n, and a ground fault has occurred in one of the cables 62p and 62n corresponding to different signals S2p and S2n. Furthermore, since the measurement signal S2n is larger than the measurement signals S1p, S1n, and S2p in the portion on the AC power supply Ea side from the position F in the cable 62n, the determination device 3 determines that a ground fault has occurred in the cable 62n.

図２は、本実施形態における判定装置の一例を示す。図２に示されるように、判定装置３は、ハイパスフィルタ３１と比較器３２とを含む。ハイパスフィルタ３１は、入力された測定信号Ｓ１ｐ，Ｓ２ｐ，Ｓ１ｎ，Ｓ２ｎのうち、交流電源Ｅａの周波数より大きい周波数成分を通過させる。測定信号Ｓ１ｐ，Ｓ２ｐ，Ｓ１ｎ，Ｓ２ｎは、交流電源Ｅａの周波数と同じ周波数成分のほかに、上述した環境磁場などに由来する雑音を含むから、ハイパスフィルタ３１は、測定信号Ｓ１ｐ，Ｓ２ｐ，Ｓ１ｎ，Ｓ２ｎのうち交流電源Ｅａの周波数と同じ周波数成分が次段の比較器３２で検出されるように、このような雑音を減衰させる。   FIG. 2 shows an example of the determination apparatus in the present embodiment. As shown in FIG. 2, the determination device 3 includes a high pass filter 31 and a comparator 32. The high pass filter 31 passes a frequency component larger than the frequency of the AC power supply Ea among the input measurement signals S1p, S2p, S1n, S2n. Since the measurement signals S1p, S2p, S1n, and S2n include noise derived from the above-described environmental magnetic field in addition to the same frequency component as the frequency of the AC power supply Ea, the high-pass filter 31 includes Such noise is attenuated so that the same frequency component as the frequency of the AC power supply Ea in S2n is detected by the comparator 32 at the next stage.

測定信号Ｓ１ｐ，Ｓ２ｐ，Ｓ１ｎ，Ｓ２ｎは、ハイパスフィルタ３１を経て、比較器３２に入力される。比較器３２は、例えば、測定信号Ｓ１ｐとＳ１ｎ，Ｓ２ｐとＳ２ｎをそれぞれ比較し、比較された２つの信号が同じか異なるかを比較結果として出力する。本実施形態において、比較器３２は、測定信号Ｓ１ｐとＳ１ｎは同じであるとの比較結果を出力し、測定信号Ｓ２ｐとＳ２ｎは異なるとの比較結果を出力する。判定装置３は、比較器３２の比較結果を受けて、測定信号Ｓ１ｐとＳ１ｎにそれぞれ対応するケーブル６１ｐと６１ｎには地絡は生じておらず、測定信号Ｓ２ｐとＳ２ｎにそれぞれ対応するケーブル６２ｐと６２ｎのいずれかに地絡が生じていると判定する。   The measurement signals S1p, S2p, S1n, and S2n are input to the comparator 32 through the high pass filter 31. For example, the comparator 32 compares the measurement signals S1p and S1n, S2p and S2n, and outputs whether the two compared signals are the same or different as a comparison result. In the present embodiment, the comparator 32 outputs a comparison result that the measurement signals S1p and S1n are the same, and outputs a comparison result that the measurement signals S2p and S2n are different. The determination device 3 receives the comparison result of the comparator 32, and no ground fault occurs in the cables 61p and 61n corresponding to the measurement signals S1p and S1n, respectively, and the cables 62p corresponding to the measurement signals S2p and S2n, respectively. It is determined that a ground fault has occurred in any of 62n.

比較器３２は、入力された測定信号Ｓのうち大きい方を比較結果として出力するものであってもよく、例えば、測定信号Ｓ２ｐとＳ２ｎの入力に対して、測定信号Ｓ２ｐの方が大きいとの比較結果を出力する。判定装置３は、比較器３２のこの比較結果を受けて、測定信号Ｓ２ｐに対応するケーブル６２ｎが地絡していると判定する。   The comparator 32 may output a larger one of the input measurement signals S as a comparison result. For example, the measurement signal S2p is larger than the input of the measurement signals S2p and S2n. Output the comparison result. The determination device 3 receives this comparison result of the comparator 32 and determines that the cable 62n corresponding to the measurement signal S2p is grounded.

＝＝＝使用方法＝＝＝
本実施形態における探索装置の使用方法を説明する。本探索装置１を用いて地絡箇所を探索する手順は、地絡ケーブル６を判定する手順と、地絡ケーブル６における地絡箇所を特定する手順とに大別されるから、以下、順を追って説明する。 === Usage ===
A method of using the search device in this embodiment will be described. The procedure for searching for a ground fault location using the search device 1 is roughly divided into a procedure for determining the ground fault cable 6 and a procedure for specifying the ground fault location in the ground fault cable 6. I will explain later.

［地絡ケーブルを判定する手順］
スイッチＳＷを操作し、交流電源Ｅａを例えば正極側ケーブル６１ｐ，６２ｐに接続する。磁気センサ２の検出コイルを正極側ケーブル６１ｐ，６２ｐに近づけ、測定信号Ｓ１ｐ，Ｓ２ｐを得る。磁気センサ２として例えばＳＱＵＩＤグラジオメータを用いることにより、微弱な変動磁場が検出される。なお、正極側ケーブル６１ｐ，６２ｐが埋設されていたり他のケーブルとともに敷設されていたりする場合でも、埋設や敷設がなされた状態のまま、正極側ケーブル６１ｐ，６２ｐに磁気センサ２の検出コイルを近づければよい。この段階では、判定装置３で比較される程度の測定信号Ｓが得られるように、ケーブル６１ｐ，６１ｎのおける任意の地点とその近傍を磁気センサ２で走査すればよい。 [Procedure for determining ground fault cable]
The switch SW is operated to connect the AC power source Ea to, for example, the positive side cables 61p and 62p. The detection coil of the magnetic sensor 2 is brought close to the positive cables 61p and 62p to obtain measurement signals S1p and S2p. By using, for example, a SQUID gradiometer as the magnetic sensor 2, a weak variable magnetic field is detected. Even when the positive-side cables 61p and 62p are buried or laid together with other cables, the detection coil of the magnetic sensor 2 is brought close to the positive-side cables 61p and 62p while being buried or laid. Just do it. At this stage, the magnetic sensor 2 may be used to scan an arbitrary point in the cables 61p and 61n and the vicinity thereof so that the measurement signal S comparable to the determination device 3 can be obtained.

次に、スイッチＳＷを切り替え、交流電源Ｅａを負極側ケーブル６１ｎ，６２ｎに接続して、磁気センサ２の検出コイルを負極側ケーブル６１ｎ，６２ｎに近づけて、測定信号Ｓ１ｎ，Ｓ２ｎを得る。ここでも、負極側ケーブル６１ｎ，６２ｎが埋設されていたり他のケーブルとともに敷設されていたりする場合に、埋設や敷設がなされた状態のまま、負極側ケーブル６１ｎ，６２ｎに磁気センサ２の検出コイルを近づければよい。また、この段階では、判定装置３で比較される程度の測定信号Ｓが得られるように、ケーブル６１ｎ，６２ｎのおける任意の地点とその近傍を磁気センサ２で走査すればよい。   Next, the switch SW is switched, the AC power source Ea is connected to the negative cables 61n and 62n, and the detection coil of the magnetic sensor 2 is brought close to the negative cables 61n and 62n to obtain the measurement signals S1n and S2n. Here again, when the negative side cables 61n and 62n are buried or laid together with other cables, the detection coil of the magnetic sensor 2 is attached to the negative side cables 61n and 62n while being buried or laid. It only has to be close. Further, at this stage, the magnetic sensor 2 may be used to scan an arbitrary point in the cables 61n and 62n and the vicinity thereof so that the measurement signal S comparable to the determination device 3 can be obtained.

そして、得られた測定信号Ｓを測定装置３に入力し、測定信号Ｓ同士を比較する。例えばＳ１ｐとＳ１ｎ、Ｓ２ｐとＳ２ｎがそれぞれ比較されるように測定信号を測定装置３に入力すると、上述したように測定信号Ｓ１ｐとＳ１ｎはほぼ同じであり、測定信号Ｓ２ｐとＳ２ｎは異なることから、測定装置３は、測定信号Ｓ１ｐとＳ１ｎに対応するケーブル６１ｐと６１ｎに地絡は生じておらず、測定信号Ｓ２ｐとＳ２ｎに対応するケーブル６２ｐと６２ｎのいずれか一方に地絡が生じている、と判定する。更に、測定信号Ｓ２ｎは、ケーブル６２ｎにおける位置Ｆより交流電源Ｅａ側を測定した信号である場合には、地絡電流Ｉｒに相当する分だけ測定信号Ｓ２ｐより大きいから、測定装置３は、大きい方の測定信号Ｓ２ｎに対応するケーブル６２ｎに地絡が生じている、と判定する。   Then, the obtained measurement signal S is input to the measurement device 3 and the measurement signals S are compared with each other. For example, when a measurement signal is input to the measurement apparatus 3 so that S1p and S1n and S2p and S2n are compared, the measurement signals S1p and S1n are substantially the same as described above, and the measurement signals S2p and S2n are different. In the measuring apparatus 3, no ground fault occurs in the cables 61p and 61n corresponding to the measurement signals S1p and S1n, and a ground fault occurs in one of the cables 62p and 62n corresponding to the measurement signals S2p and S2n. Is determined. Further, when the measurement signal S2n is a signal obtained by measuring the AC power supply Ea side from the position F in the cable 62n, the measurement device 3 is larger than the measurement signal S2p by an amount corresponding to the ground fault current Ir. It is determined that a ground fault has occurred in the cable 62n corresponding to the measurement signal S2n.

なお、地絡ケーブルの判定のための手順において、ケーブル６２ｎにおいて地絡が生じている位置Ｆより負荷５２側に磁気センサ２を当てた場合には、測定信号として０が出力される。その場合には、磁気センサ２で測定中のケーブル６に地絡が生じていると判定される。   In the procedure for determining the ground fault cable, when the magnetic sensor 2 is applied to the load 52 side from the position F where the ground fault occurs in the cable 62n, 0 is output as the measurement signal. In that case, it is determined that a ground fault has occurred in the cable 6 being measured by the magnetic sensor 2.

また、例えば、第３の負荷５３（図示せず）の負極側ケーブル６３ｎ（図示せず）が、ケーブル６２ｎにおける位置Ｆより上流側の位置Ａ（図示せず）から分岐している場合であって、ケーブル６２ｎに対する測定信号Ｓ２ｎほかに、ケーブル６３ｎに対する測定信号Ｓ３ｎも０であるときには、ケーブル６２ｎが地絡ケーブルであると判定されるとともに、ケーブル６２ｎの位置Ａより上流側において地絡が生じていると判定される。   Further, for example, this is a case where the negative electrode side cable 63n (not shown) of the third load 53 (not shown) branches from a position A (not shown) upstream of the position F in the cable 62n. When the measurement signal S2n for the cable 62n and the measurement signal S3n for the cable 63n are also 0, it is determined that the cable 62n is a ground fault cable, and a ground fault occurs upstream of the position A of the cable 62n. It is determined that

［地絡箇所を特定する手順］
上述した手順において地絡が生じていると判定されたケーブルについて、地絡箇所を特定するために次の作業が行われる。 [Procedure for identifying ground fault location]
The following work is performed to identify the ground fault location for the cable determined to have a ground fault in the above-described procedure.

まず、交流電源Ｅａが地絡ケーブル（本実施形態ではケーブル６２ｎ）に接続されるようにスイッチＳＷを切り替える。スイッチＳＷの切替は例えば手動で行われる。   First, the switch SW is switched so that the AC power supply Ea is connected to the ground fault cable (cable 62n in the present embodiment). The switch SW is switched manually, for example.

次に、磁気センサ２の検出コイルをケーブル６２ｎに近づけた状態で、検出コイルをケーブル６２ｎの軸方向に沿って走査する。走査は、例えば、手動により、ケーブル６２ｎにおける交流電源Ｅａ側から位置Ｆを経て負荷５２側に向かって行われる。その場合、磁気センサ２から出力される測定信号Ｓ２ｎは、対地充電電流ＩＣｇに地絡電流Ｉｒが重畳して流れることに伴う比較的大きな値から、位置Ｆを境として０に変化する。判定装置３は、測定信号Ｓ２ｎがこのように変化したときにおける磁気センサ２の検出コイルの位置の近傍を、地絡箇所と判断する。   Next, the detection coil is scanned along the axial direction of the cable 62n while the detection coil of the magnetic sensor 2 is brought close to the cable 62n. Scanning is performed manually, for example, from the AC power supply Ea side of the cable 62n toward the load 52 side through the position F. In that case, the measurement signal S2n output from the magnetic sensor 2 changes from a relatively large value that accompanies the flow of the ground fault current Ir to the ground charging current ICg to 0 at the position F as a boundary. The determination device 3 determines the vicinity of the position of the detection coil of the magnetic sensor 2 when the measurement signal S2n changes in this way as a ground fault location.

なお、上述のようにして地絡箇所が特定された後、該当するケーブルが人手によって引っ張りだされ、目視により損傷の有無が確認される。本実施形態においては、ケーブル６を掘り出したり引き出したりするような時間と労力を要する作業は、地絡箇所が特定された後に行われるので、簡便な作業により地絡箇所が特定される。   In addition, after a ground fault location is specified as mentioned above, the applicable cable is pulled out manually and the presence or absence of damage is confirmed visually. In the present embodiment, the work requiring time and labor for digging out and pulling out the cable 6 is performed after the ground fault location is specified, and therefore the ground fault location is specified by a simple operation.

［第２実施形態］
図３を参照して、本発明の第２実施形態における地絡箇所の探索装置について説明する。なお、本実施形態における探索装置１’は、判定装置において第１実施形態における探索装置１と相違し、その他の構成は同じである。よって、本実施形態において、第１実施形態と同様の部材および装置には共通の符号を付すとともに、説明を省略する。 [Second Embodiment]
With reference to FIG. 3, the ground fault location search apparatus in 2nd Embodiment of this invention is demonstrated. The search device 1 ′ in the present embodiment is different from the search device 1 in the first embodiment in the determination device, and the other configurations are the same. Therefore, in the present embodiment, the same members and devices as those in the first embodiment are denoted by common reference numerals and the description thereof is omitted.

図３は、本実施形態における判定装置の概略を示す図である。図３に示されるように、判定装置３’は、同期検波器３３と比較器３４とを含む。
同期検波器３３は、交流電源Ｅａと同じ周波数で測定信号Ｓ（Ｓ１ｐ，Ｓ２ｐ，Ｓ１ｎ，Ｓ２ｎ）を検波する。対地充電電流ＩＣｇおよび地絡電流Ｉｒならびにこれら電流に伴う変動磁場は、交流電源Ｅａの周波数とほぼ同じ周波数で変動することから、測定信号Ｓから交流電源Ｅａの周波数とほぼ同じ周波数成分を検出して地絡判定のために用いることで、地絡判定の確実性が向上する。なお、判定装置３’は例えばロックインアンプである。 FIG. 3 is a diagram showing an outline of the determination apparatus in the present embodiment. As shown in FIG. 3, the determination device 3 ′ includes a synchronous detector 33 and a comparator 34.
The synchronous detector 33 detects the measurement signal S (S1p, S2p, S1n, S2n) at the same frequency as the AC power supply Ea. Since the ground charging current ICg, the ground fault current Ir, and the fluctuating magnetic field accompanying these currents fluctuate at substantially the same frequency as the frequency of the AC power supply Ea, the frequency component substantially the same as the frequency of the AC power supply Ea is detected from the measurement signal S By using it for ground fault determination, the reliability of ground fault determination is improved. The determination device 3 ′ is, for example, a lock-in amplifier.

同期検波器３３の出力は比較器３４に入力されるところ、比較器３４の動作は、第１実施形態における比較器３２の動作と同様であるので、説明を省略する。   Since the output of the synchronous detector 33 is input to the comparator 34, the operation of the comparator 34 is the same as the operation of the comparator 32 in the first embodiment, and thus description thereof is omitted.

探索装置１’の使用方法は第１実施形態における探索装置１の使用方法と同じであるので、説明を省略する。   Since the usage method of the search device 1 'is the same as the usage method of the search device 1 in the first embodiment, the description thereof is omitted.

前述したとおり、スイッチＳＷは、直流電源ＥＤと負荷５（５１，５２）との間に接続されている正極側ケーブル６１ｐ，６２ｐおよび負極側ケーブル６１ｎ，６２ｎに対して、交流電源Ｅａを選択的に接続する。また、磁気センサ２は、交流電源Ｅａが正極側ケーブル６１ｐ，６２ｐに接続されているとき、正極側ケーブル６１ｐ，６２ｐを流れる電流による変動磁場を測定して第１測定信号Ｓ１ｐ，Ｓ２ｐを出力し、交流電源Ｅａが負極側ケーブル６１ｎ，６２ｎに接続されているとき、負極側ケーブル６１ｎ，６２ｎを流れる電流による変動磁場を測定して第２測定信号Ｓ１ｎ，Ｓ２ｎを出力する。また、判定装置３は、第１測定信号Ｓ１ｐ，Ｓ２ｐと第２測定信号Ｓ１ｎ，Ｓ２ｎとを比較し、第１測定信号Ｓ１ｐ，Ｓ２ｐと第２測定信号Ｓ１ｎ，Ｓ２ｎが異なる場合、正極側ケーブル６１ｐ，６２ｐおよび負極側ケーブル６１ｎ，６２ｎのいずれか一方に地絡が発生していると判定する。本実施形態において、測定信号Ｓ１ｐとＳ１ｎはほぼ同じであるから、ケーブル６１ｐと６１ｎには地絡は生じていないと判定され、測定信号Ｓ２ｐとＳ２ｎは異なるからケーブル６２ｐと６２ｎのいずれかに地絡が生じていると判定される。従って、複数本のケーブルがまとめて埋設されたり敷設されたりしている場合でも、速やかにかつ簡便に、地絡しているケーブルが特定される。   As described above, the switch SW selectively selects the AC power source Ea for the positive side cables 61p and 62p and the negative side cables 61n and 62n connected between the DC power source ED and the load 5 (51, 52). Connect to. In addition, when the AC power supply Ea is connected to the positive cables 61p and 62p, the magnetic sensor 2 measures the fluctuating magnetic field due to the current flowing through the positive cables 61p and 62p and outputs the first measurement signals S1p and S2p. When the AC power supply Ea is connected to the negative cables 61n and 62n, the magnetic field fluctuating due to the current flowing through the negative cables 61n and 62n is measured and the second measurement signals S1n and S2n are output. Further, the determination device 3 compares the first measurement signals S1p and S2p with the second measurement signals S1n and S2n, and when the first measurement signals S1p and S2p are different from the second measurement signals S1n and S2n, the positive-side cable 61p. 62p and the negative side cables 61n, 62n are determined to have a ground fault. In the present embodiment, since the measurement signals S1p and S1n are substantially the same, it is determined that no ground fault has occurred in the cables 61p and 61n, and the measurement signals S2p and S2n are different, so that either one of the cables 62p and 62n is grounded. It is determined that an entanglement has occurred. Therefore, even when a plurality of cables are buried or laid together, a grounded cable is identified quickly and easily.

また、判定装置３は、第１測定信号Ｓ１ｐ，Ｓ２ｐと第２測定信号Ｓ１ｎ，Ｓ２ｎとを比較し、正極側ケーブル６１ｐ，６２ｐおよび負極側ケーブル６１ｎ，６２ｎのうち第１測定信号Ｓ１ｐ，Ｓ２ｐと第２測定信号Ｓ１ｎ，Ｓ２ｎの値が大きい方のケーブルに地絡が発生していると判定する。本実施形態において、測定信号の値が大きい方のケーブル６２ｎに地絡が生じていると判定されるから、更に速やかにかつ簡便に、地絡しているケーブルが特定される。   In addition, the determination device 3 compares the first measurement signals S1p and S2p with the second measurement signals S1n and S2n, and the first measurement signals S1p and S2p of the positive cables 61p and 62p and the negative cables 61n and 62n It is determined that a ground fault has occurred in the cable having the larger value of the second measurement signals S1n and S2n. In the present embodiment, since it is determined that a ground fault has occurred in the cable 62n having the larger measurement signal value, the ground fault cable is identified more quickly and simply.

また、磁気センサ２は、正極側ケーブル６１ｐ，６２ｐまたは負極側ケーブル６１ｎ，６２ｎを流れる電流による変動磁場を、検出コイルを介して測定する。変動磁場を、磁気センサ２の本体から分離した検出コイルで検出することで、磁気センサ２の本体が環境磁場等の影響を受けないので、正確な測定信号Ｓを得ることができる。よって、正確な地絡判定が可能となる。   Moreover, the magnetic sensor 2 measures the fluctuation | variation magnetic field by the electric current which flows through the positive electrode side cables 61p and 62p or the negative electrode side cables 61n and 62n via a detection coil. By detecting the fluctuating magnetic field with a detection coil separated from the main body of the magnetic sensor 2, the main body of the magnetic sensor 2 is not affected by an environmental magnetic field or the like, so that an accurate measurement signal S can be obtained. Therefore, accurate ground fault determination is possible.

また、交流電源Ｅａは、略６００Ｈｚの周波数の交流電圧を出力する。このとき、対地充電電流ＩＣｇおよび地絡電流Ｉｒは略６００Ｈｚで変動し、これら電流に伴う微弱な変動磁場も略６００Ｈｚで変動する。測定信号Ｓは、変動磁場に対応する略６００Ｈｚの周波数成分と、環境磁場等に由来する雑音とを含むところ、略６００Ｈｚの周波数成分は、雑音に埋もれることなく判定装置３において検出される。よって、正確な判定結果により確実に地絡ケーブルを特定することができる。   The AC power supply Ea outputs an AC voltage having a frequency of approximately 600 Hz. At this time, the ground charging current ICg and the ground fault current Ir fluctuate at about 600 Hz, and the weak fluctuating magnetic field accompanying these currents fluctuates at about 600 Hz. The measurement signal S includes a frequency component of approximately 600 Hz corresponding to the varying magnetic field and noise derived from the environmental magnetic field or the like. The frequency component of approximately 600 Hz is detected by the determination device 3 without being buried in the noise. Therefore, it is possible to reliably identify the ground fault cable based on the accurate determination result.

また、判定装置３は、第１測定信号Ｓ１ｐ，Ｓ２ｐおよび第２測定信号Ｓ１ｎ，Ｓ２ｎから交流電源Ｅａの周波数と略同一の周波数成分が検出されるように、第１測定信号Ｓ１ｐ，Ｓ２ｐおよび第２測定信号Ｓ１ｎ，Ｓ２ｎのうち交流電源Ｅａの周波数より高い周波数成分を通過させるハイパスフィルタを含む。測定信号Ｓ（Ｓ１ｐ，Ｓ２ｐ，Ｓ１ｎ，Ｓ２ｎ）に含まれる雑音をハイパスフィルタ３１によって減衰させることによって、測定信号Ｓ（Ｓ１ｐ，Ｓ２ｐ，Ｓ１ｎ，Ｓ２ｎ）のうち交流電源Ｅａの周波数と同じ周波数成分は、判定装置３によって確実に検出される。従って、確実に地絡ケーブルを特定することができる。   Further, the determination device 3 detects the first measurement signals S1p, S2p and the second measurement signals S1p, S2p and the second measurement signals S1n, S2n so that the frequency components substantially the same as the frequency of the AC power supply Ea are detected. 2 The high-pass filter which passes the frequency component higher than the frequency of AC power supply Ea among measurement signals S1n and S2n is included. By attenuating noise included in the measurement signal S (S1p, S2p, S1n, S2n) by the high-pass filter 31, the same frequency component as the frequency of the AC power supply Ea in the measurement signal S (S1p, S2p, S1n, S2n) is obtained. , It is reliably detected by the determination device 3. Therefore, it is possible to reliably identify the ground fault cable.

また、判定装置３は、第１測定信号Ｓ１ｐ，Ｓ２ｐおよび第２測定信号Ｓ１ｎ，Ｓ２ｎから交流電源Ｅａの周波数と略同一の周波数成分が検出されるように、第１測定信号Ｓ１ｐ，Ｓ２ｐおよび第２測定信号Ｓ１ｎ，Ｓ２ｎから交流電源Ｅａの周波数と略同一の周波数成分を選択する同期検波器３３を含む。測定信号Ｓ（Ｓ１ｐ，Ｓ２ｐ，Ｓ１ｎ，Ｓ２ｎ）から交流電源Ｅａの周波数とほぼ同じ周波数成分を選択することによって、測定信号Ｓの比較が容易になり、地絡判定の確実性が増す。   Further, the determination device 3 detects the first measurement signals S1p, S2p and the second measurement signals S1p, S2p and the second measurement signals S1n, S2n so that the frequency components substantially the same as the frequency of the AC power supply Ea are detected. 2 includes a synchronous detector 33 that selects a frequency component substantially the same as the frequency of the AC power supply Ea from the measurement signals S1n and S2n. By selecting substantially the same frequency component as the frequency of the AC power supply Ea from the measurement signal S (S1p, S2p, S1n, S2n), the comparison of the measurement signal S is facilitated, and the reliability of the ground fault determination is increased.

また、磁気センサ２は、正極側ケーブル６１ｐ，６２ｐおよび負極側ケーブル６１ｎ，６２ｎを軸方向に沿って走査する。更に、判定装置３は、正極側ケーブル６１ｐ，６２ｐに地絡が発生していると判定した場合、磁気センサ２が正極側ケーブル６１ｐ，６２ｐを走査したときの第１測定信号Ｓ１ｐ，Ｓ２ｐの変化から地絡箇所を判定し、負極側ケーブル６１ｎ，６２ｎに地絡が発生していると判定した場合、磁気センサ２が負極側ケーブル６１ｎ，６２ｎを走査したときの第２測定信号Ｓ１ｎ，Ｓ２ｎの変化から地絡箇所を判定する。測定信号Ｓ（Ｓ１ｐ，Ｓ２ｐ，Ｓ１ｎ，Ｓ２ｎ）は、磁気センサ２がケーブル６２ｎにおける地絡箇所Ｆの近傍を走査するとき、ある値から０に、あるいは逆に、０からある値に変化する。このように変化する測定信号Ｓの値に着目して地絡箇所を探索することで、地絡箇所の特定を迅速かつ簡便に行うことができる。   Moreover, the magnetic sensor 2 scans the positive side cables 61p and 62p and the negative side cables 61n and 62n along the axial direction. Further, when the determination device 3 determines that a ground fault has occurred in the positive cables 61p and 62p, the change in the first measurement signals S1p and S2p when the magnetic sensor 2 scans the positive cables 61p and 62p. The ground fault location is determined, and when it is determined that a ground fault has occurred in the negative side cables 61n and 62n, the second measurement signals S1n and S2n when the magnetic sensor 2 scans the negative side cables 61n and 62n. The ground fault location is determined from the change. The measurement signal S (S1p, S2p, S1n, S2n) changes from a certain value to 0, or vice versa, when the magnetic sensor 2 scans the vicinity of the ground fault location F in the cable 62n. By searching for the ground fault location by paying attention to the value of the measurement signal S changing in this way, the ground fault location can be identified quickly and easily.

また、地絡箇所の探索方法では、直流電源と負荷との間に接続されている正極側ケーブル６１ｐ，６２ｐおよび負極側ケーブル６１ｎ，６２ｎに対して、交流電源Ｅａを選択的に接続する。そして、交流電源Ｅａが正極側ケーブル６１ｐ，６２ｐに接続されているとき、正極側ケーブル６１ｐ，６２ｐを流れる電流による変動磁場を測定して第１測定信号Ｓ１ｐ，Ｓ２ｐを出力し、交流電源Ｅａが負極側ケーブル６１ｎ，６２ｎに接続されているとき、負極側ケーブル６１ｎ，６２ｎを流れる電流による変動磁場を測定して第２測定信号Ｓ１ｎ，Ｓ２ｎを出力する。そして、第１測定信号Ｓ１ｐ，Ｓ２ｐと第２測定信号Ｓ１ｎ，Ｓ２ｎとを比較し、第１測定信号Ｓ１ｐ，Ｓ２ｐと第２測定信号Ｓ１ｎ，Ｓ２ｎが異なる場合、正極側ケーブル６１ｐ，６２ｐおよび負極側ケーブル６１ｎ，６２ｎのいずれか一方に地絡が発生していると判定する。本実施形態においては、上述したとおりケーブル６１ｐと６１ｎには地絡は生じておらず、ケーブル６２ｐと６２ｎのいずれかに地絡が生じていると判定される。従って、複数本のケーブルがまとめて埋設されたり敷設されたりしている場合でも、速やかにかつ簡便に、地絡しているケーブルが特定される。   In the ground fault location searching method, the AC power source Ea is selectively connected to the positive side cables 61p and 62p and the negative side cables 61n and 62n connected between the DC power source and the load. When the AC power source Ea is connected to the positive side cables 61p and 62p, the magnetic field fluctuating due to the current flowing through the positive side cables 61p and 62p is measured and the first measurement signals S1p and S2p are output. When connected to the negative side cables 61n and 62n, the fluctuation magnetic field due to the current flowing through the negative side cables 61n and 62n is measured and the second measurement signals S1n and S2n are output. Then, the first measurement signals S1p and S2p are compared with the second measurement signals S1n and S2n. When the first measurement signals S1p and S2p are different from the second measurement signals S1n and S2n, the positive side cables 61p and 62p and the negative side It is determined that a ground fault has occurred in either one of the cables 61n and 62n. In the present embodiment, as described above, it is determined that no ground fault has occurred in the cables 61p and 61n, and a ground fault has occurred in either of the cables 62p and 62n. Therefore, even when a plurality of cables are buried or laid together, a grounded cable is identified quickly and easily.

なお、上記第１及び第２実施形態は、本発明の理解を容易にするためのものであり、本発明を限定して解釈するためのものではない。本発明は、その趣旨を逸脱することなく、変更、改良され得るとともに、本発明にはその等価物も含まれる。   In addition, the said 1st and 2nd embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

例えば、交流電源Ｅａの周波数は、判定装置３において測定信号Ｓから微弱な変動磁場の成分が検出される程度であればよく、数百Ｈｚでも６００Ｈｚより高くてもよい。   For example, the frequency of the AC power supply Ea is only required to be such that a weak variable magnetic field component is detected from the measurement signal S in the determination device 3, and may be several hundred Hz or higher than 600 Hz.

１ 地絡箇所の探索装置
２ 磁気センサ
３ 判定装置
Ｅａ 交流電源
ＳＷ スイッチ DESCRIPTION OF SYMBOLS 1 Ground fault location search device 2 Magnetic sensor 3 Judgment device Ea AC power supply SW switch

Claims (8)

交流電源と、
直流電源と負荷との間に接続されている正極側ケーブルおよび負極側ケーブルに対して、前記交流電源を選択的に接続するスイッチと、
前記交流電源が正極側ケーブルに接続されているとき、前記正極側ケーブルを流れる電流による変動磁場を測定して第１測定信号を出力し、前記交流電源が負極側ケーブルに接続されているとき、前記負極側ケーブルを流れる電流による変動磁場を測定して第２測定信号を出力する測定装置と、
前記第１測定信号と前記第２測定信号とを比較し、前記第１測定信号と前記第２測定信号が異なる場合、前記正極側ケーブルおよび前記負極側ケーブルのいずれか一方に地絡が発生していると判定する判定装置と
を備えることを特徴とする地絡箇所の探索装置。 AC power supply,
A switch for selectively connecting the AC power supply to the positive cable and the negative cable connected between the DC power supply and the load;
When the AC power supply is connected to the positive cable, the first measurement signal is output by measuring the variable magnetic field due to the current flowing through the positive cable, and the AC power supply is connected to the negative cable. A measuring device for measuring a variable magnetic field due to a current flowing through the negative cable and outputting a second measurement signal;
When the first measurement signal and the second measurement signal are compared, and the first measurement signal and the second measurement signal are different, a ground fault occurs in one of the positive side cable and the negative side cable. A ground fault location searching device comprising: a determination device that determines that the ground fault is present. 前記判定装置は、前記第１測定信号と前記第２測定信号とを比較し、前記正極側ケーブルおよび前記負極側ケーブルのうち前記第１測定信号と前記第２測定信号の値が大きい方のケーブルに地絡が発生していると判定することを特徴とする請求項１に記載の地絡箇所の探索装置。   The determination device compares the first measurement signal and the second measurement signal, and the cable having the larger value of the first measurement signal and the second measurement signal among the positive cable and the negative cable. The ground fault location searching device according to claim 1, wherein it is determined that a ground fault has occurred. 前記測定装置は、前記正極側ケーブルまたは前記負極側ケーブルを流れる電流による変動磁場を検出コイルを介して測定するセンサを含むことを特徴とする請求項１または２に記載の地絡箇所の探索装置。   3. The ground fault location searching device according to claim 1, wherein the measuring device includes a sensor that measures, via a detection coil, a variable magnetic field due to a current flowing through the positive cable or the negative cable. . 前記交流電源は、略６００Ｈｚの周波数の交流電圧を出力することを特徴とする請求項１ないし３のいずれかに記載の地絡箇所の探索装置。   4. The ground fault location searching device according to claim 1, wherein the AC power source outputs an AC voltage having a frequency of approximately 600 Hz. 前記判定装置は、前記第１測定信号および前記第２測定信号から前記交流電源の周波数と略同一の周波数成分が検出されるように、前記第１測定信号および前記第２測定信号のうち前記交流電源の周波数より高い周波数成分を通過させるハイパスフィルタを含むことを特徴とする請求項１ないし４のいずれかに記載の地絡箇所の探索装置。   The determination device is configured to detect the AC signal of the first measurement signal and the second measurement signal so that a frequency component substantially the same as the frequency of the AC power supply is detected from the first measurement signal and the second measurement signal. The ground fault location searching device according to any one of claims 1 to 4, further comprising a high-pass filter that allows a frequency component higher than the frequency of the power supply to pass therethrough. 前記判定装置は、前記第１測定信号および前記第２測定信号から前記交流電源の周波数と略同一の周波数成分が検出されるように、前記第１測定信号および前記第２測定信号から前記交流電源の周波数と略同一の周波数成分を選択する同期検波器を含むことを特徴とする請求項１ないし４のいずれかに記載の地絡箇所の探索装置。   The determination device detects the AC power source from the first measurement signal and the second measurement signal so that a frequency component substantially the same as the frequency of the AC power source is detected from the first measurement signal and the second measurement signal. The ground fault location searching device according to any one of claims 1 to 4, further comprising a synchronous detector that selects a frequency component that is substantially the same as the first frequency component. 前記測定装置は、前記正極側ケーブルおよび前記負極側ケーブルを軸方向に沿って走査し、
前記判定装置は、前記正極側ケーブルに地絡が発生していると判定した場合、前記測定装置が前記正極側ケーブルを走査したときの前記第１測定信号の変化から地絡箇所を判定し、前記負極側ケーブルに地絡が発生していると判定した場合、前記測定装置が前記負極側ケーブルを走査したときの前記第２測定信号の変化から地絡箇所を判定する
ことを特徴とする請求項１ないし６のいずれかに記載の地絡箇所の探索装置。 The measuring device scans the positive cable and the negative cable along the axial direction,
When the determination device determines that a ground fault has occurred in the positive cable, the determination device determines a ground fault location from a change in the first measurement signal when the measurement device scans the positive cable; When it is determined that a ground fault has occurred in the negative cable, the ground fault location is determined from a change in the second measurement signal when the measuring device scans the negative cable. Item 7. The ground fault location searching device according to any one of Items 1 to 6. 直流電源と負荷との間に接続されている正極側ケーブルおよび負極側ケーブルに対して、交流電源を選択的に接続し、
前記交流電源が正極側ケーブルに接続されているとき、前記正極側ケーブルを流れる電流による変動磁場を測定して第１測定信号を出力し、前記交流電源が負極側ケーブルに接続されているとき、前記負極側ケーブルを流れる電流による変動磁場を測定して第２測定信号を出力し、
前記第１測定信号と前記第２測定信号とを比較し、前記第１測定信号と前記第２測定信号が異なる場合、前記正極側ケーブルおよび前記負極側ケーブルのいずれか一方に地絡が発生していると判定する
ことを特徴とする地絡箇所の探索方法。 Selectively connect an AC power supply to the positive and negative cables connected between the DC power supply and the load,
When the AC power supply is connected to the positive cable, the first measurement signal is output by measuring the variable magnetic field due to the current flowing through the positive cable, and the AC power supply is connected to the negative cable. A variable magnetic field due to the current flowing through the negative cable is measured and a second measurement signal is output;
When the first measurement signal and the second measurement signal are compared, and the first measurement signal and the second measurement signal are different, a ground fault occurs in one of the positive side cable and the negative side cable. A method of searching for a ground fault location, characterized by determining that the
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CN111711129B (en) * 2020-06-29 2021-08-17 中国化学工程第十一建设有限公司 Construction method for searching and repairing fault of outer sheath of single-core high-voltage cable

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JPH0755873A (en) * 1993-08-20 1995-03-03 Kaihatsu Denki Kk Discrimination method of ground fault of dc control circuit
JPH1010178A (en) * 1996-06-25 1998-01-16 Toshiba Corp Method and apparatus for detecting partial discharge of gas insulated machine
JPH11220830A (en) * 1998-02-02 1999-08-10 Tokyo Electric Power Co Inc:The Method for identifying fault point on power cable
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